SQL递归层次结构非常慢

Question

所以我刚刚得到一个任务来优化 SQL 查询，该查询构建产品、内部产品、制造操作、操作细节和项目（制造产品所需）的层次结构树。该查询返回 218k 行，工作正常，但构建树大约需要 15-18 秒。是否可以优化该查询，使其大约需要 2-3 秒？如果我添加 @ProductID 作为此过程的参数并执行

WHERE ProductID = @ProductID

从产品表中选择后，它工作得非常快，但树不完整，因为如果我为其构建树的产品是内部产品，它的父产品不会出现在树中。 将所有这些表加载到 C# 应用程序并在那里构建所有层次结构会更快吗？

我对所有想法持开放态度。以下是有问题的查询

  ALTER PROCEDURE [dbo].[ProductProduct_selectHierarchy_v2]
WITH EXECUTE AS CALLER
AS
BEGIN
WITH ProductProductHierarchy (
    ProductID
    ,ItemProductID
    ,LEVEL
    ,UniqueID
    ,ParentID
    ,RowType
    ,ProductDetailID
    ,ProductProductDetailBindID
    ,ManufactoryOperationID
    ,ItemID
    )
AS (
    -- Anchor member definition
    SELECT dbo.Product.ProductID AS ProductID
        ,Product.ProductID AS ItemProductID
        ,0 AS LEVEL
        ,Cast(cast(Product.ProductID AS NVARCHAR(40)) + '' AS NVARCHAR(50)) AS UniqueID
        ,cast('' AS NVARCHAR(50)) AS ParentID
        ,1 AS RowType
        ,NULL AS ProductDetailID
        ,NULL AS ProductProductDetailBindID
        ,NULL AS ManufactoryOperationID
        ,NULL AS ItemID
    FROM dbo.Product

    UNION ALL

    -- Recursive member definition
    SELECT e.ProductID
        ,e.ItemProductID
        ,LEVEL + 1
        ,Cast(Cast(d.UniqueID AS NVARCHAR(40)) + '_' + cast((e.ItemProductID) AS NVARCHAR(10)) AS NVARCHAR(50)) AS UniqueID
        ,Cast(d.UniqueID AS NVARCHAR(50)) AS ParentID
        ,1 AS RowType
        ,NULL AS ProductDetailID
        ,NULL AS ProductProductDetailBindID
        ,NULL AS ManufactoryOperationID
        ,NULL AS ItemID
    FROM dbo.ProductProduct AS e
    INNER JOIN ProductProductHierarchy AS d ON e.ProductID = d.ItemProductID

    UNION ALL

    SELECT NULL AS ProductID
        ,NULL
        ,LEVEL + 1
        ,Cast(Cast(d.UniqueID AS NVARCHAR(40)) + '_' + cast((e.ProductDetailID) AS NVARCHAR(10)) AS NVARCHAR(50)) AS UniqueID
        ,Cast(d.UniqueID AS NVARCHAR(50)) AS ParentID
        ,2 AS RowType
        ,e.ProductDetailID AS ProductDetailID
        ,e.ProductProductDetailBindID AS ProductProductDetailBindID
        ,NULL AS ManufactoryOperationID
        ,NULL AS ItemID
    FROM dbo.ProductProductDetailBind AS e
    INNER JOIN ProductProductHierarchy AS d ON e.ProductID = d.ItemProductID

    UNION ALL

    SELECT NULL AS ProductID
        ,NULL
        ,LEVEL + 1
        ,Cast(Cast(d.UniqueID AS NVARCHAR(40)) + '_' + cast((e.ManufactoryOperationID) AS NVARCHAR(10)) AS NVARCHAR(50)) AS UniqueID
        ,Cast(d.UniqueID AS NVARCHAR(50)) AS ParentID
        ,3 AS RowType
        ,NULL AS ProductDetailID
        ,NULL AS ProductProductDetailBindID
        ,e.ManufactoryOperationID AS ManufactoryOperationID
        ,NULL AS ItemID
    FROM dbo.ProductDetailOperation AS e
    INNER JOIN ProductProductHierarchy AS d ON e.ProductProductDetailBindID = d.ProductProductDetailBindID

    UNION ALL

    SELECT NULL AS ProductID
        ,NULL
        ,LEVEL + 1
        ,Cast(Cast(d.UniqueID AS NVARCHAR(40)) + '_' + cast((e.ItemID) AS NVARCHAR(10)) AS NVARCHAR(50)) AS UniqueID
        ,Cast(d.UniqueID AS NVARCHAR(50)) AS ParentID
        ,4 AS RowType
        ,NULL AS ProductDetailID
        ,NULL AS ProductProductDetailBindID
        ,NULL AS ManufactoryOperationID
        ,e.ItemID AS ItemID
    FROM dbo.ProductItem AS e
    INNER JOIN ProductProductHierarchy AS d ON e.ProductID = d.ItemProductID
    )
-- Statement that executes the CTE
SELECT CASE 
        WHEN RowType = 1
            THEN ProductName + '<' + ProductCode + '>'
        WHEN RowType = 2
            THEN ProductDetail.ProductDetailName
        WHEN RowType = 3
            THEN ManufactoryOperation.ManufactoryOperationName
        ELSE Item.ItemName
        END AS ProductName
    ,UniqueID
    ,ProductProductHierarchy.ParentID
    ,Product.ProductID
    ,RowType
FROM ProductProductHierarchy
LEFT OUTER JOIN Product ON Product.ProductID = ProductProductHierarchy.ItemProductID
    AND RowType = 1
LEFT OUTER JOIN ProductDetail ON ProductDetail.ProductDetailID = ProductProductHierarchy.ProductDetailID
    AND RowType = 2
LEFT OUTER JOIN ManufactoryOperation ON ManufactoryOperation.ManufactoryOperationID = ProductProductHierarchy.ManufactoryOperationID
    AND RowType = 3
LEFT OUTER JOIN Item ON Item.ItemID = ProductProductHierarchy.ItemID
    AND RowType = 4
OPTION (MAXRECURSION 0)

结束

Answer 1

看起来您正在有效地构建一组异构行，我通常会尽量远离这些行。如果需要，使用递归获取产品树，然后将操作、项目等作为单独的结果集拉入。像你一样混合行类型很可能会导致令人头疼的问题（不仅仅是性能问题）。

在不了解您的应用程序的全部功能的情况下，我不能说您应该从数据库中检索这些项目的最佳方式，但我肯定会从可能的问题开始。